Baseline OCT data will be obtained right after stenting. The remaining coronary artery, if diseased and required PCI treatment, will be treated during the angiographic and OCT follow-up as a staged procedure. Patients will be randomly assigned into 5 groups with equal number, receiving a follow-up coronary angiogram with OCT from 2, 3, 4, 5 and 6 months interval post-intervention. Each patient will serve as his/her own control comparing the 2 types of stents. At 9-month post-intervention, all patients will receive a second follow-up coronary angiogram with OCT. All OCT data analyses will be performed in a blinded fashion by a core laboratory. Phone follow up will be carried out for cardiac events at 1 year and 2 year of post intervention.